1. Field of the Invention
The present invention relates to failsafe workholding clamping assemblies for holding work pieces.
2. Description of Related Art
As shown in JP2002046005, it is known to provide a failsafe workholding clamping assembly that maintains a collet in a closed position unless an opening force is applied. Failsafe workholding clamping assemblies are advantageous because they will not accidentally release a work piece, even if power to the closing mechanism is lost (e.g., loss of drawbar force, pneumatic force, hydraulic force, etc.).
Conventional failsafe workholding clamping assemblies include drivers (e.g., compression springs) that close the collets in the absence of a counteracting opening force. Large drivers are required to provide the large closing forces necessary to keep collets closed. Unfortunately, such large drivers make conventional workholding clamping assemblies large, axially long, and radially wide.